The correct answer is to change the instance type to a larger size, such as moving from a t3.medium to a t3.large, because this action vertically scales the instance to provide more vCPUs and memory, directly addressing the high CPU utilization during peak hours without over-provisioning resources. This approach, known as scaling up, targets the specific bottleneck—CPU capacity—by upgrading the instance family size rather than adding more instances or unrelated resources. On the AWS Certified SysOps Administrator Associate SOA-C02 exam, this scenario tests your understanding of vertical scaling versus horizontal scaling, with a common trap being the temptation to add Auto Scaling groups or Spot Instances, which either over-provision or fail to improve performance. A key memory tip is to think of "scale up" as a bigger engine in the same car, not adding more cars—vertical scaling fixes a single overloaded instance, while horizontal scaling adds more instances and risks waste.
SOA-C02 Cost and Performance Optimization Practice Question
This SOA-C02 practice question tests your understanding of cost and performance optimization. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A SysOps administrator notices that an EC2 instance's CPU utilization is consistently above 90% during peak hours. Which action will improve performance without over-provisioning resources?
Why wrong: Spot Instances are cheaper but not more powerful.
B
Increase the number of EBS volumes attached to the instance.
Why wrong: EBS volumes affect storage performance, not CPU.
C
Change the instance type to a larger size, such as moving from t3.medium to t3.large.
Larger instance type provides more CPU capacity.
D
Configure Auto Scaling to add more instances during peak hours.
Why wrong: Scaling out adds instances but may not address single-instance CPU bottleneck; could be cost-effective but not performance improvement per instance.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Change the instance type to a larger size, such as moving from t3.medium to t3.large.
Option C is correct because changing the instance type to a larger size (e.g., from t3.medium to t3.large) vertically scales the instance, providing more vCPUs and memory to handle the increased CPU load during peak hours. This directly addresses the high CPU utilization without over-provisioning, as you are only scaling up the specific resource that is constrained. Spot Instances (A) do not improve performance; they offer lower cost but same performance. Increasing EBS volumes (B) does not affect CPU performance. Auto Scaling (D) adds more instances (horizontal scaling), which can over-provision if the single instance's capacity is sufficient after a vertical scale-up.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use Spot Instances instead of On-Demand.
Why it's wrong here
Spot Instances are cheaper but not more powerful.
✗
Increase the number of EBS volumes attached to the instance.
Why it's wrong here
EBS volumes affect storage performance, not CPU.
✓
Change the instance type to a larger size, such as moving from t3.medium to t3.large.
Why this is correct
Larger instance type provides more CPU capacity.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure Auto Scaling to add more instances during peak hours.
Why it's wrong here
Scaling out adds instances but may not address single-instance CPU bottleneck; could be cost-effective but not performance improvement per instance.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse horizontal scaling (Auto Scaling) with vertical scaling, assuming adding more instances is always the best performance fix, but the question explicitly asks to avoid over-provisioning, making a single larger instance the more efficient choice.
Detailed technical explanation
How to think about this question
Vertical scaling (changing instance type) directly increases the number of vCPUs and baseline CPU credits (for T3 instances) or dedicated CPU performance (for M5/C5 families), allowing the instance to sustain higher CPU utilization without throttling. For T3 instances, moving from t3.medium (2 vCPUs, unlimited mode) to t3.large (2 vCPUs but higher baseline and more CPU credits) provides more sustained CPU capacity. In contrast, horizontal scaling via Auto Scaling requires re-architecting the application for distributed processing and may introduce latency from load balancers.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Cost and Performance Optimization — This question tests Cost and Performance Optimization — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Change the instance type to a larger size, such as moving from t3.medium to t3.large. — Option C is correct because changing the instance type to a larger size (e.g., from t3.medium to t3.large) vertically scales the instance, providing more vCPUs and memory to handle the increased CPU load during peak hours. This directly addresses the high CPU utilization without over-provisioning, as you are only scaling up the specific resource that is constrained. Spot Instances (A) do not improve performance; they offer lower cost but same performance. Increasing EBS volumes (B) does not affect CPU performance. Auto Scaling (D) adds more instances (horizontal scaling), which can over-provision if the single instance's capacity is sufficient after a vertical scale-up.
What should I do if I get this SOA-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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